FEATURE
course. And nearly all US dairy cows are
given prophylactic, intramammary drug
infusions—typically penicillins or other
beta-lactam drugs—to prevent mastitis.
Antibiotics are also used as pesticides. The
US Environmental Protection Agency, for
example, is in the process of re-approving
the use of streptomycin for wholesale
spraying on apple, pear and nectarine
trees to control citrus canker and citrus
greening disease.
Tennessee microbiologists Michelle Therrien
and Justin Simpson process carbapenem-resistant
Enterobacteriaceae specimens. Photo: TDH DLS
Even if we have perfect
antibiotic prescribing and use,
AR would still be a problem, largely
because of the transmission of
[existing] resistant pathogens.”
Michael Craig, MPP
“Whenever and wherever you
use antibiotics, resistance is
going to follow”
The problem of antibiotic resistance (AR)
has been decades in the making. James
“Albert” Burks, IV, MLS(ASCP), RN, who
oversees carbapenem-resistance testing
at the TDH Division of Laboratory Services
explained that antibiotic research and
development “slacked off” beginning
in the mid-1980s, when an array of
potent antibacterial agents was readily
available. At the same time, he said,
physicians began prescribing antibiotics
for conditions like sinus infections,
now known to be mostly viral and
unresponsive to antibacterial drugs.
“Patients were taking [antibiotics] until
they felt better when the lifecycle of
the virus was complete; they weren’t
taking the full regimen,” said Burks.
Consequently, mildly drug-resistant
pathogens were able to survive and
evolve.
Outside the healthcare arena, antibiotics
have also been overused in veterinary and
agricultural settings. In fact, agricultural
usage of antibiotics far exceeds their
healthcare usage. Farmers administer
the drugs not only to treat acute animal
illness, but also to prevent illness and
to enhance animal growth. According to
one estimate, about 90% of pigs raised
for food in the US get tetracyclines or
similar drugs in their feed as a matter of
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LAB MATTERS Summer 2019
Global developments have exacerbated
the problem. In 2010, India was the
world’s largest consumer of antibiotics
for human health, followed by China.
According to researchers Ramanan
Laxminarayan and Ranjit Roy Chaudhury,
a perfect storm of poor public health
systems, high rates of infectious disease,
inexpensive antibiotics and rising
incomes has led to the proliferation
of resistant pathogens in many parts
of the world and especially the BRICS
countries—Brazil, Russia, India, China and
South Africa. Increased demand for meat
and poultry in places like India has fueled
even greater agricultural antibiotic use.
Michael Craig, MPP, CDC’s senior advisor
for AR, said, “Whenever and wherever
you use antibiotics, resistance is going
to follow.” He said, “We take for granted
sometimes that antibiotics are really
the scaffolding that makes surgical
procedures possible, organ transplants
possible, invasive disease treatments
possible. All of those are risky, and people
susceptible to infections are vulnerable.
When antibiotics start to be ineffective,
the risk-benefit profiles of those
treatments change; doctors might not
Tennessee’s GC AR Lab Network Team (from l to r): Robin
Rasnic, Arianna Allgood, Erica Terrell, Brielle Davis and
Henrietta Hardin. Photo: TDH DLS
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